Improvement in stop-valves



` C. F'. M U R DUCK.

III

` WITNESSES- Stop-Valves. Y

Patented Aug. 18,1874.

HUH:

Jil/florney UNITED STATES PATENT OFFICE.

CHARLES F. MURDOCK, OF DETRCIT, MICHIGAN.

IM PROVEMENT IN STOP-VALVES.

Specification forming part of Letters Patent No. 154,271, dated August 18, 1874; application filed March 21, 1874.

To all whom it may concern:

Be it known that I, CHAnLEs F. MUE- DOCK, of Detroit, in the county ot' Wayne and State of Michigan, have invented certain Improvements in Stop-Valves, of which the following is a specification:

This invention consists in a novel construction and arrangement of the'two valveplates.

Figure y1 is a longitudinal central section Vof the valve, and Fig. 2 a side or edge view ot' the two valve-plates.

A represents the case or body of the valve; B, the stem or spindle by which the valve-plates are moved, and C and D the two valve-plates.

The body is constructed in the same general form as those now in use, with two valve-seats, c, which approachl each other toward the back or bottom of the case. The valve-stem passes out through a stuffing-box in the end or extension of the case or body, and has its outer end provided with a handwheel, as usual. The stem, instead ot' having a singlethread cut upon it, as usual, has a lefthand thread cut upon one end, and

a right-hand thread cut upon the other, as

shown in Fig. 1. One of these threads engages inthe neck ofthe case or body,.so that, as the stem is turned, it is moved endwise; while the other thread engages with the valve-plates, to move them lengthwise on the stem in the same direction that the latter is moving. Y

The' consequence of this arrangement is, that the valve plates are moved at twice the spoed given them by a single thread, for the reason that, while they are carried along on the stem, the stem is also moved endwise in the same direction. v

In my present valve, the only moving parts beside the screw are the two valve-plates C and D. The former is provided on its back with a stud or block, c, having on its outsidev a spherical protuberance, d, to form a bearing for the other valve-plate, D, and having through its center a threaded hole to receive the screw-stem, as shown in Fig. 1.

The plate D isl` formed with an annular ange, e, on its back. The plate C also has on its back, at the inner or lower side, two arms, g, and, at its upper edge, with a lip,

h, al1 of which extend down outside of the flange e, as shown in both gures.

The plate D, being mounted on the spherical bearing, is free to tip in any direction 5 while its ange c, being inside of the arms g and lip h, prevents it from sliding out of place.

`On turning the screw in the proper direction, the plates are carried inward, and forced tightly home between the two converging seats. The plate C is carried directly by the screw, while the plate D is carried by the protnberance d and lip h.

When the screw has its motion reversed, the plates are drawn back, and the valve opened, the plate D being held in position and aided in its movement by the arms g of plate C.

By having the spherical or ball-and-sock et joint between the plates they are both left free to adapt themselves to "their respective seats.

It will be seen that, as the plate C is mounted directly on the screw, a positive motion is imparted to it, so that there is no dauger of its being stopped or wedged fast by coming in contact with the slight obstructions which it will often meet.

By passing the screw through the solid block on the valve-plate, the valve is rendered extremelysimple, cheap, andstrong, while at the saine time both plates are permitted to adapt themselves to their seats independently ot' each other.

Having thus described my invention, what I claim is- 1. In combination with the valve-plate C, having the block or nut c and the spherical bearing d formed solidly on its back, the screw-stem B, passing through the block or nut, and the valve-plate D, mounted on the bearing, as shown.

2. In combination with the screw B, the plate C, having the block c, spherical protuberance d, arms g, and lip h, and the plate D, mounted on the protuberance, and having the annular ange c, as shown and described.

CHARLES F. MURDOCK.

Witnesses:

J. MCKENNEY, W. W. DODGE. 

